As computing devices, such as servers, disk drives, etc., continue to become increasingly more complex, with more transistors and logic gates on each chip, the various components of the computing devices become increasingly sensitive to cosmic rays (i.e., high energy particles that originate from the sun) and internally excited vibrations. In addition, such complex computing devices are more difficult to cool properly using air cooling techniques. For example, as disk drives increase in complexity, the disk drives become increasingly sensitive to vibration-induced destruction. Vibrations affect disk drives in this manner because the density of information stored on disk drives has grown exponentially, resulting in a write head that is required to hit a track that is less than 20 nanometers in width, while the write head is floating only 7 nanometers above the disk surface. Such a configuration makes the read and write performance of the disk drive very sensitive to internally excited vibrations, such as the vibrations that result from air cooling fans that intersect structural resonances within the computing device.
Further, complex computing devices are typically associated with soft error rates (SERs) from transient single-event upsets (SEUs). SEUs occur in both logic and memory chips and are typically due to high energy neutrons from cosmic rays. Because of increases in logic gate density and drops in voltage of successive generations of chips, the sensitivity of each new chip design with respect to neutron-induced SERs is also increasing.
The altitude of computing devices significantly affects the sensitivity and cooling of computing devices. For example, at higher altitudes, where the air is thinner, the blades of internal cooling fans turn faster (i.e., the fans have more revolutions per minute (RPMs)). This is because fan speeds are typically controlled by voltage, and are not locked into a fixed RPM. When fans operate faster, the vibrations created by the fans increases, which can lead to disk drive failures, as described above. Thus, often times, testing computing devices in a controlled enviromnent, such as a lab, at one altitude may not be sufficient to ensure that the computing devices will operate in the same manner upon being distributed to a field or data center at a customer site at a different altitude.
One way to obtain the altitude of a particular computing device is to install altimeter sensors that directly measure the altitude of the computing devices. In some cases, installing altimeter sensors for a large number of computing devices can become costly. Further, customers can specify the altitude for their location when configuration settings are obtained for computing devices that are specifically tested for the customers; however, many times, customers do not know this information or cannot obtain an accurate measure of the altitude at their specific location before the computing device is configured for the customer site.